Bakery-product-stacking method and apparatus

ABSTRACT

Bakery product units are received from a depanner and/or slicer at a marshaling station in two discrete rows. Product units from the two rows are then released in a controlled manner and are advanced in timed relation with or without inversion of the units in one or both rows. The product units in one row move gradually into superposed relation with corresponding product units of the second row and each superposed pair of product units is then engaged and advanced in unison until stacked registering relationship of each superposed pair is attained.

United States Patent [72] Inventors [2i Appl. No. [22] Filed [45 IPatented [73 Assignee [54] BAKERY-PRODUCT-STACKING METHOD AND PrimaryExaminer-Andres l-l. Nielsen Anorneywynne and F inken ABSTRACT: Bakeryproduct units are received from a depanner and/or slicer at a marshalingstation in two discrete rows. Product units from the two rows are thenreleased in a ll d d d d t' d lt- 'th 38 c 22 Drum contro e manner anare a ance m une re a lOll W] or 1 1 without inversion of the units Inone or both rows. The [52] [1.5. CI. 198/35, product units in one rowmove gradually into superposed rela- 198/33 tion with correspondingproduct units of the second row and [51] ht. B65g 57/00 each superposedpair of product units is then engaged and ad- [50] Field 01 Sarch 198/33R, vanced in unison until stacked registering relationship of each 35; 314/6 F superposed pair is attained.

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SHEET 7 BF 9 PATENTED AUB 3 I97! SHEET 8 OF 9 will! 5 my BH ssrtizav-raonuc'r-s'racxnvc ME'HIOD AND APPARATUS 1 BACKGROUND OF THE INVENTIONMachines and devices are known in the prior art for stacking bakeryproducts, such as roll clusters, as the products are. traveling from adepanner or slicer toward packaging equipment. One example of such aprior art machine is found in US. Pat. No. 3,322,314, issued May 30;1967, to Irving, Jr. et al. As disclosed in this patent, bakery productunits are advanced from a marshaling zone to a turnover station: Forwardmovement of one product unit in each lateral pair of units is arrestedwhile the'companion unit is liftedand turned over laterally and isdropped freely ontop of the second unit in stacked relationship. Thestacked product units are then advanced from the. turnover station by aconveyor toward packaging equipment or the like- While thepatentedmachine operates satisfactorily, it has certain inherent deficiencies,the most important of which is lack of desirable speed in stacking theproduct units. Additionally, the mode of operation involving lifting ofone product unit and allowing it to fall freely through a considerabledistance onto the': second unit is somewhat awkward and slow andrequires extremely accurate timing and alignment of parts.

The invention method and apparatus improves greatly upon the prior artin thatthe invention is much fasterand more reliable in achievingaccurate stacking and reg'ntration of product units with or withoutinversion of one or both units in each' pair and with the elimination ofthe dropping or free-falling movement of one product unit upon theother, noted above. In

the, present invention, laterally related product units" are.

moved in a controlled manner from a marshaling station and optionallythe units in'either of two discrete rows or both rows may. be quickly.inverted individually without being displaced on their main path ofmovement. The product units in one row are gradually moved diagonallytowardsuperposed relation' with corresponding product units'of thesecond row and companion superposed units are then engaged by a commonconveying means and advanced gently into stacked registering relationwithout any appreciable dropping orfree falling of the top product-unitin the stacked pair. The process is continuous, very reliable and quiterapid. Furthermore, .the apparatus employed in the practice of themethod is relatively simple'in' construction, fully adjustable andeconomical.

SUMMARY OF THE INVENTION Laterallyrelatedpairs of. product units areadvanced awayfrom .the inverting zone and one unit of each pair isconveyed upwardly slightly and is carried diagonally tovvardthe otherproduct unit in the related pair untilthe'twounits are super-'- poast'rapusher means cornmonto the superposed engages thepairand'furtheradvanceswhile they move gently into stacked relation and are further'alignedrbyanabutment member and an aligningairjet. Fromthis point, theaccurately stacked-product units can be earried'to a packaging machineor the like by a conveyor.

BRIEF'DESCRIPTION OF THE DRAWINGS" no. 1a a Wee plan view of themethodand ap- Y paratus embodying the invention;

FIG. 2 is a partly diagrammatic side elevation of the apparatus;

FIG. 3 is a plan view of the apparatus with parts removed and omittedfor clarity of illustration;

FIG. 4 is a fragmentary plan'view of product holddown means omitted inFIG. 3;

FIG. 5 is an enlarged fragmentary side elevational view, partly insection and partly broken away, showing the infeed conveyor and productholddown means;

FIG. 6 is an enlarged transverse vertical section taken on line 6-6 ofFIG. 3;

FIG. 7 is a similar section taken on line 7-7 of FIG. 4;

.FIG. 8 is a transverse vertical section taken on line 8-8 of FIG. 9:

FIG. 9 is a fragmentary plan view on an enlarged scale of that portionof the apparatus depicted in FIG. .8 adjacent the turnover device andassociated elements;

FIG. 10 is a fragmentary longitudinal vertical section taken on line10-10 of FIG. 8; 7

FIG. 11 is a similar and enlarged section taken on line 1 l-'II of FIG.8;

0.12 is a vertical section taken on line 12-12 of FIG. 11;

FIGS. 13a through 13c are partly diagrammatic side elevational views ofthe turnover device in various positions during a cycle of operation; 1

FIG. 14 is an enlarged fragmentary plan view of the discharge endportion of the apparatus adjacent the diagonal crossover means andassociated components;

FIG. 15 is a longitudinal vertical section taken on line 15-15 of FIG.I4;'

FIG.I6 is an enlarged fragmentary side elevation of a chain propelledpusher on the diagonal crossover device;

17 is a diagrammatic perspective view of chain propelled pushing fingeror pin elements and the means for keeping them erect during movement;

FIG. 18 is a partly diagrammatic viewsimilar to FIG. 10 showing amodification.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to thedrawings in detail, wherein like numerals designate like partsthroughout the same, reference is made first to FIGS.2 and 3 which showthe apparatus in its entirety.

In these figures, a supporting framework is shown for positioningtheseveral working components of the apparatus at a convenientelevationabove the floor and this framework includes end leg units 26 and 27asshown and a pair of main upperhorizontal side rails 28 constitutingthe bed of the apparatus: The details of the framework 25 may be variedand are not important.

Continuing to refer to FIGS. 2 and 3, the product intake end of theapparatus constitutes a product-marshaling station 29,

following which is a rapid infeed means 30 for the leading I productunits at the marshaling station 29. A product inverting or turnovermeans 31 is disposed close to the infeed means 30 to-receiveproductunits directly therefrom and following the turnover means is aconveyor section 32 of the apparatus which carries discrete rows of theproduct units in a controlled manner toward a stacking and dischargestation. A diagonal crossover conveyor device 33 is provided to conveyproduct units from one row into superposed relation with companion unitsof the second row. Finally, the apparatus includes a discha'rge'stationor means 34 where the pairs of product units are brought into stackedregistering relation and proper alignment prior to delivery topaekagingequipment or the like.

MARSHALING STATION station 29, "referring to FIGS. 2 through 6,comprises two laterally spaced groups of horizontal parallellongitudinal product intake conveyor belts 35 which are endless andengage about rollers 36, 37 and 38, as shown. The belts 35' arerelatively slack so that they may yield readily under the force ofcertain product holddown means, to be described. Closely beneath theconveyor belts 35 and midway between adjacent pairs of the belts, FIG.6, are stiff rods 39 which engage the bottoms of the product units whenthe latter are clamped by the said holddown means. These rods 39 arefixed relative to the belts 35 and are supported on the frame structure25 in any desired manner.

Above the belts 35 are substantially horizontal product holddown grids40 and 41 comprising rigidly connected spaced parallel rods 42, FIGS. 4,and 6. The two grids 40 and 41 are independently operable above therespective groups of belts 35- and their purpose is to clamp the productunits moving with the relatively slack belts 35 against the stationaryrods 39 to thereby arrest the movement of the product units while thebelts slide harmlessly thereunder.

The forward ends of the grids 40 and 41 are independently raised andlowered by fluid pressure operated vertical cylinder piston units 43disposed near and inwardly of the frame said rails 28, FIGS. 5 and 7.The extensible and retractable piston rods of these units are pivotallyconnected at their tops with crank arms 43 rigid with a supportingcross'shaft, to be described. The cylinder piston units 43 are alsobodily adjustable vertically relative to the apparatus framework bymeans of a vertical screw shaft 44 carrying a nut member 45 connected at46 to the bottom of one unit 43. The lower end of screw shaft 44 carriesa sprocket gear 47 connected with a horizontal transverse sprocket chain48 which in turn engages a sprocket gear 49 on the lower end of a secondvertical screw shaft near the opposite side of the apparatus, carrying anut 50 connected at 51 with the second cylinder piston unit 43. Byturning the hand wheel 52 of screw shaft 44, both units 43 may be bodilyraised and lowered in unison. The units 43 are utilized to take andlower the holddown grids 40 and 41 with respect to bakery products of agiven size or thickness. When products having a significantly greater orlesser thickness must be accommodated by the apparatus, the screw shaft44 is utilized to raise or lower the units 43.

The rear ends of the grids 40 and 41, FIG. 5, are suspended from crankarms 60 by bracket members 61 pivoted thereto, the arms 60 being carriedon a cross shaft 62 supported at its ends by bearing plates 63 on theside rails 28. A two-part cross-shaft 64-64 mounted on upstandingbearing plates 65 and a center bearing 65' near the forward ends of thegrids 40 and 41 carries crank arms 66 from which the forward ends of theholddown grids aresuspended by bracket means 67. The previouslydescribed crank arms 43' connected with the raising and lowering units43 are secured to the cross-shaft sections 64-64, as noted.

In order to assembly or marshal the bakery product units such asclusters of hamburger rolls, in two discrete rows at the marshalingstation 29, pairs of laterally spaced parallel guide bars 53 and 54 areprovided closely above the belts 35. The guide bars are-carried bydependent arms 55 on transverse screw shafts 56 and 57. The parallelscrew shafts are operatively connected by sprocket gearing 58 and theshaft 56 carries a hand wheel 59 to facilitate turning it. By utilizingthis hand wheel, the spacing between the pairs of guide bars may beadjusted for proper 'guidanceof the product units in the two discreterows.

RAPID I'NFEED STATION The mentioned. infeed means 30 which advanceslaterally pairs of product units away from the marshaling station intimed relation comprises upper and lower relatively large diameterinfeed rollers 68 and 69. mounted on rotatable shaha 70 and 71 to turntherewith, said shafts being in vertical alignment. The rollers 68 and69 are each formed in two sections 72 and 73 and 69' and 69",respectively, FIG. 6. As best shown in FIG. 10, the infeed rollers havea solid core and an outer heavy layer of soft compressible material suchas foam rubber or foam plastic so that the rollers are resilient.

74 to provide clearance for the belts 35 passing forwardly to the guideroller 38, FIG. 10. The upper runs of belts 35 are generally tangent tothe top of roller 69 so that these belts may carry the product units tothe rapid infeed rollers when the units are released by holddown grids40 and 41. The two sections 72 and 73 of the upper infeed roller areentirely covered with the compressible material, whereas this materialis applied in strips to the lower roller segments 74.

As shown in FIG. 2, the lower roller 69 is driven through suitablegearing. 75 which may include clutch and brake means, not shown, bymeans of which the infeed rollers are intermittent in operation. Thegearing 75 derives power from a main motor 76, and additional gearing 77connected with the motor 76 drives a main transverse drive shaft 78 fromwhich other powered components of the apparatus are driven, as will bedescribed.

Driving power from the shaft 71 and roller 69 is transmitted to theupper shaft 70 and roller 68 by conventional right angular drives 79 and80 whose details need not be described. As viewed in FIG. 2, the upperinfeed roller 68 will turn counterclockwise whereas the lower roller 69will turn clockwise so that the product units passing therebetween willbe fed away from the marshaling station 29 by the soft sponge infeedrollers.

The upper roller 68 is vertically adjustable through the medium ofvertical screw shafts 81, one of which has a hand wheel 82 thereon. Theseveral screw shafts 81 are connected for turning in unison by chaingearing 83, and when the screw shafts are turned, they cause the raisingor lowering of bearing assemblies 84 within which the shaft 70 isjoumaled and supported. The shaft 71 for roller 69 remains at a fixedelevation. Vertical drive shafts 85 interconnecting the right angulardrives 79 and 80 move upwardly and downwardly with the drives 80 whenthe shaft 70 is vertically adjusted by turning the hand wheel 82. Theshafts 85 transmit power between the drives 79 and 80 in all adjustedpositions and this construction is conventional regarding the shafts 85.

TURNOVER STATION The turnover means 31 comprises vertical support plates86 secured rigidly to the frame rails 28 and extending thereabove for aconsiderable distance. Pairs of vertical guide bars 87 are securedrigidly to the plates 86 close to their inner sides, and verticallyshiftable crossheads 88 engage the guide bars 87 and are adjustablethereon under the influence of vertical screw shafts 89 also near theplates 86, one of which is equipped at its top end with a hand crank 90.The two screw shafts 89 are interconnected by chain gearing 91 so as toturn in unison for raising and lowering the crossheads 88 which havescrewthreaded engagement with the adjusting screw shafts. The crossheads88 carry a pair of spaced transverse horizontal bars 92 at one elevationand these bars are raised and lowered in unison by turning the crank 90.

The product inverting or turnover mechanism shown in detail in FIGS. 10through 13 constitutes an important feature of the invention andcomprises vertical frame sides 93 suspended fromthe bars 92, as shown,whereby the entire mechanism carried by the frame sides 93 may, whenrequired, be manually adjusted laterally along the bars 92 to positionthe turnover device at either side of the apparatus for invertingproduct units ineeither discrete row. As shown, the turnover mechanismis positioned at the left-hand side of the apparatus as viewed in FIGS.6 to 9 and will be described in this position. The remaining elements ofthe turnover mechanism, now to be described, are bodily carried by theframe sides 93 and are thus movable therewith when the mechanism israised and lowered by the screw shafts 89 or shifted laterally, asdescribed.

Referring now to FIGS. 10 through 13, the turnover mechanism furthercomprises a pair of spaced parallel plates 94 forming between them arelatively shallow passage 95 for The lower roller 69, FIG. 6, is alsoformed in plural segments 75 product units which are to be invertedwhile remaining on their same longitudinal path of travel, that is,without lateral displacement. The two plates 94'forming this passage 95are secured as at 96, FIG. 12, to the inner race 97 of a large ballbearing 98 whose outer race is fixedly held in the frame side 93, FIGS.11 and 12. The same construction is present on both sides of theturnover mechanism for attaching the ball bearing to the element 93 andfor attaching the plates 94 to the inner race of the ball bearing.

The mechanism further includes a reciprocating pusher plate or member 99which traverses the passage 95 from one open end thereof to the otherend, as shown in FIGS. 13a to 13:. The pusher plate 99 is guided in itsmovement by guide rods 100 which are also secured to the internal races97 of the two bearings. The opposite sides of the pusher plate unitcarry extensions 101 which are slidably mounted on the rods 100, as bestshown in FIG. 12.

A drive chain 102 for the turnover mechanism travels in a D-shaped pathas depicted in FIG. 11 including an upper horizontal run and a lowerapproximately semicircular run. One such chain is provided at each sideof the mechanism and is connected as at 103, FIG. 12, with one of theelements 101 of the pusher plate. Each chain 102 engages threeequidistantly spaced sprocket gears 104, as indicated, and the shaft 105of one sprocket gear is powered by another sprocket gear 106, connectedby a chain 107 with an overhead sprocket gear 108 on one of the bars 92which is rotational. The bar 92 and sprocket gear 108 in turn are driventhrough a conventional right angular drive unit 109, vertically movablewith the bar 92 on a vertical drive shaft 110 journaled for rotation inbearings 111 which are stationary. A slot 112, FIG. 10, is provided inthe adjacent plate 86 to allow vertical movement-of the end extension ofthe rotary bar 92 connected with the drive 109. The vertical shaft 110,FIG. 2, is driven near the bottom of the apparatus through anotherconventional right angular drive unit 113 in turn deriving its powerfrom gearing 114 ultimately connected with and driven by the main motor76. Intermediate parts of the main drive gearing leading from the motor76 have been omitted from the drawings for simplicity and because suchgearing is conventional and need not be fully shown for a properunderstanding of the invention. It should be apparent, however, thatwhen the vertical drive shaft 110 is driven, power is applied to the baror shaft 92 carrying sprocket gears 108 and through the related chainsI07 and associated gearing shown in FIGS. 11 and 12, the drive chains102 will be operated for producing the cycle of momement of the turnovermechanism graphically depicted in FIGS. 13al3e.

As shown in these figures, the upper straight run 115 of each chain 102constitutes the travel segment of the pusher bar 99, whereas the lowercurved run 1 16 constitutes the rotational segment of the drive for theparallel plates 94 and associated elements including the interiorbearing race 97. The turnover mechanism in its entirety is actually aconstant speed intermittent motion mechanism. As shown in FIGS. 13a-13e,the pusher bar 99 is stationary and does not reciprocate relative to thetwo plates 94 while the turning of the plates is taking place as inFIGS. 13d and 13e.

Referring first to FIG. 13a, the mode of operation is essentially asfollows: regarding the turnover means 31. The shaft 110 is driving thechains 107 and in turn sprocket gears 104 and D-shaped chains 102. InFIG. 130, the rotational portion of the turnover cycle has just beencompleted, and the pusher bar 99 is at the rear end of the passage 95between the two plates 94, and is moving toward the forward end of thepassage and discharging the inverted product unit 117. At this moment,the rapid infeed rollers 68 and 69 start to rotate in the,

direction of the arrows and feed the product unit 117 into the pasage 95immediately behind the moving pusher bar, as

and is now moving at a relatively high velocity to slide completely intothe passage until stopped by'pusher bar 99 as shown in FIG. 13c. Therapid infeed rollers 68 and 69 are still rotating as shown by the arrowsin FIG. 13b until product unit 117 completely disengages the rollers.The holddown grid elevates when product unit 117 is about three-fourthsbeyond the nips of the rollers 68 and 69 and allows product unit 117" tomove forwardly with belts 35. Rollers 68 and 69 propel product unit 117at a much higher velocity than the belts 35 move product unit 1 17".

In FIG. 130, product unit 117' is almost completely discharged frompassage 95 and pusher bar 99, together with plates 94, starts on itscircular path as shown by the arrow. Product unit 117 is now completelyinside of passage 95 and against pusher bar 99. The infeed rollers 68and 69 have stopped and product unit 117" has moved into the spacevacated by the product unit 117. The holddown grid 40 moves downimmediately behind product unit 117" and before this unit reaches infeedrollers 68 and 69.

In FIG. d, d,product unit 117' is completely discharged from the passage95 and pusher bar 99, with plates 94, has started on its semicircularpath of movement. Product unit 117" is being held back by the stationaryrollers 68 and 69 while the belts 35 are sliding beneath it. Productunits 117" are being held back by the grid 40 at this time.

FIG. 133 shows product unit 117 moving toward the discharge end of theapparatus illustrated in FIG. 14. Product unit 117 is now partiallyinverted and is being held by pusher bar 99 and plates 94. Product unit1 17" is in position to start a new cycle as soon as pusher bar 99reaches the position shown initially in FIG. 13a.

. The pusher bar 99 is constantly moving on the D-shaped path at theconstant speed of the chains I02. Relative to the passage 95, the pusherbar is moving only on its horizontal run and during this time thepassage 95 is stationary or nonrotating. On the lower semicircular pathof movement of the pusher bar, FIGS. 13d and 13a, there is no movementof the further illustrated in FIGS. 13b and 13c. At this moment, as

pusher bar in the passage relative to the plates 94, but the passagesitself is being turned upside down along with the product unit 117within it. Actually, therefore, the pusher bar 99 is never stationary inspace although it does become stationary relative to the plates 94.

As shown in FIGS. 8 and 9, a relatively short conveyor belt section 118occupies the space laterally adjacent the turnover mechanism in theother product row beneath the bars 92. As stated, the turnover mechanismcan be shifted laterally on the bars '92 to handle product units movingin either row through the apparatus. Additionally, the entire turnovermechanism can be raised to a nonuse position above the conveyor bedwhere no inverting of the product in either row is desired. For example,the products in one row may enter the apparatus already inverted withrespect to the products in the second row. In some cases, a pair of theturnover mechanisms 31 may be employed side-by-side instead of a singlemechanism and in these respects the method and apparatus is highlyversatile.

In the arrangement shown in the drawings, the conveyor section 118 isemployed to bridge the gap in the conveyor bed which would otherwise beoccupied by the turnover mechanism. If this mechanism is shiftedlaterally to service the other row of products, then the conveyorsection 118 may be employed'at the position of the turnover mechanism inFIGS. 8 and 9.

, The conveyor sections 118 are raised and lowered independently byswinging on the axes of their shafts 126 and 126'. The shaft 126' has ahand crank on the operators side of the apparatus which is turned forraising and lowering the conveyor section 118 on the near side. Alocking pin 119 is provided to lock the'handle 120 and the associatedconveyor section in the raised or lowered position. The conveyor section118 on the far side of the apparatus is raised and lowered by anotherhand crank 120' connected with a transmission shaft 120" operatingsprocket gearing on the far side of the apparatus, said gearingincluding a sprocket gear 182 on the APPARATUS CONVEYOR SECTION Thepreviously mentioned downstream conveyor section 32 of the apparatusfollows immediately after the turnover means 31. The shaft 121, FIG. 9,is powered by suitable gearing from the main drive motor 76 leading to asprocket gear 122 on this shaft. The narrow belts 123 engage rollers 125on the shaft 121, as stated, and also engage drive rollers 124 on theconveyor sections 118. The rollers 125 also engage and drive strip ortape belts 127 and 128 in the two rows or product paths, FIGS. 3 and 14.The belts 127 and 128 engage additional rollers 129 and 130 asubstantial distance downstream from the rollers 125 as seen in FIG. 2.This figure also shows that the belts 127 slope downwardly somewhat fromthe rollers 125 whereas the belts 128 slope upwardly. To effect thisarrangement, the roller 130 is disposed above rollers 129.

CROSSOVER SECTION The downstream end of the conveyor section formed bybelts 127 terminates atthe rear ends of stationary horizontal bars 131over which the product units may slide. These bars 131 are parallel andspaced apart laterally equidistantly to provide longitudinal slotsbetween them for an important purpose, to be described. The bars 131extend to the extreme discharge end of the apparatus in FIGS. 14 and 15and are suitably supported on the apparatus framework.

The conveyor section formed by the belts 128 carries the product unitsfrom one row forwardly and slightly upwardly toward the rear intake endof a diagonal generally troughlike crossover conveyor or mechanism,previously designated 33 in its entirety. This mechanism includes abottom stationary plate 132 arranged between upstanding sidewalls 133and 134, the latter being suspended from elevated frame portions 135 and136 which span the apparatus diagonally from sideto-side. The forwardend of the crossover mechanism is rendered vertically adjustable as bestshown in FIG. 2 by means of screw shafts 137 having threaded connectionswith lugs 138 on the sidewalls 133 and 134. The screw shafts 137 areconnected by gearing 139 at the tops thereof and one shaft is equippedwith a hand crank 140 for turning.

A slotted intake ramp 141 at the rear of the crossover mechaniam allowsthe belts 128 to feed the product units 117 onto the bottom plate 132 ina smooth manner where the belts pass around the roller 130. Pluralflights 142 are provided to propel the product units through thediagonal crossover mechanism and these flights are connected at thesides of the mechanism with endless chains 143 including upper and lowerruns which are both above the bottom plate 132 at all times. The chainengage suitable guide sprockets 144 at the ends of the crossovermechanism. The several flights 142 are parallel to each other and are atright angles to the belts 127 and 128 and fixed bars 131. As shown inFIG. 14, the flights extend diagonally between their propelling chains143. Each flight carries a forwardly projecting blade 145 rigidtherewith and extending at right angles thereto. As shown in FIGS. 1 and14, the flights 142 and their blades 145 sweep each product cluster orunit 117 diagonally across the plate 132 from one product row toward theother row while maintaining the squareness and alignment of the clusterfor ultimate registration with like clusters moving over the bars 131,as will be further described. The blades 145 are therefore parallel tothe bars 131.

The several flights 142 are maintained erect at all times during theirmovement with the chains 143 by erecting links 146 having small rollers147, FIG. 15, which travel on the bottom plate 132 at the lower runs ofthe chains and also travel on an erecting cam track 148 secured to thesidewall 134 near the upper run of the adjacent chain 143. As the chains143 continuously cycle in the direction of the arrows in FIG. 2, theflights 142 pass downwardly between the sprocket gears 144 and move inbehind the product units 117 at the discharge ends of the belts 128 andbegin to engage and push the product units from the ramp 141 onto andacross the bottom plate 132. At the forward extremity of the crossovermechanism, where the flights 142 begin to rise for movement rearwardly,they will disengage the product unit 117 after depositing the same ontoa slotted forward extension 149 of the bottom plate or apron 132. Theslots 150 of extension 149 are directly over and in vertical alignmentwith the slots between the bars 131. The extension 149 tenninates aconsiderable distance forwardly of the chains 143, as shown. The

bars 131 continue on to the discharge end of the apparatus somewhatbeyond the crossover mechaniam, FIGS. 14 and 15.

The chains 143 of the crossover conveyor mechanism are powered in theproper direction by a diagonal drive shaft 151 having sprocket gears toengage the chains and, through a universal joint 152 and input shaft153, power to turn the shaft 151 is derived from the main power source76 through intermediate chain gearing, not shown.

Arranged generally beneath the spaced bars 131 and extending slightlyunder the downstream ends of the belts 127, FIG. 15, is a pusherconveyor structure comprising upright pins or pusher fingers 154arranged in transverse rows and spaced in the rows so that the fingersmay project up through the slots between the several bars 131 andultimately through the slots 150 in the plate 132 and its extension 149.At their lower ends, the upright fingers 154 are anchored to crossbarsor flights 155 which in turn are connected with endless drive chains 156on opposite sides of the group of bars 131. The chains 156 are driven inunison and engage the necessary guiding sprocket gears 157, 158 and 159as best shown in FIG. 15 to impart to the flexible chains the desiredconfiguration and path of movement. As shown in FIG. 15, the upper runsof the chains 156 are in two levels 1560 and 156b, fora purpose to bedescribed. The lower runs 1560 of chains 156 travel near the extremebottom of the apparatus so that the tops of the fingers 154 at this timeare well below the bars 131 and the belts 127. The chains 156 arepowered through gearing from the main drive 76 which interlocks with thedrive for the shaft 151 and chains 143 of the crossover mechanismwhereby these two conveyor means are locked in synchronism.Additionally, it should be mentioned that the drive gearing for theturnover mechanism, FIGS. 11 and 12, is mechanically locked with thedrives of the crossover mechanism and the conveyor chains 156 so thatthe apparatus is properly timed and synchronized. The details of thegearing necessary to achieve this are conventional and all of thegearing need not be shown, as stated.

Means to maintain the pusher fingers 154 erect at all times is providedin the form of a third endless chain 160, FIGS. 14 and 17, outwardly ofthe outboard chain 156 and offset rearwardly thereof by another set ofguiding sprocket gears 161, 162 and 163 carried by shafts which arespaced rearwardly of the shafts supporting the chains 156 as indicatedat 164 and 165 in FIG. 15. The erecting chain moves in unison with thetwo chains 156 and its sole purpose is to keep the fingers 154 erect atall times. To accomplish this, erecting links 166 for the fingers 154interconnect the outside pair of chains 156 and 160, as shown best indiagrammatic FIG. 17 but also shown in FIG. 14.

As the rows of pusher fingers 154 rise at the rear vertical runs 167 ofthe conveyor chains 156, they will enter between the discharge endportions of the belts 127 and engage behind the product units 117 beingdelivered by these belts onto the stationary bars 131. That is to say,the fingers 154 will begin to push the product units over the bars 131by engaging the product units as shown. The belt rollers I29 and theirsupport arms 168, FIG. 15, areseparated and individual to the belts 127so that the fingers can pass up and through the spaces between the beltsand enter the slots between 'the bars 131 without obstruction.

The fingers 154 continue to push the product units 117 toward thedischarge end of the apparatus while at the elevation of the chain runs1560. At this time, the tops of the fingers 154 are below the bottomplate 132 of the crossover mechanism and its extension 149 having theslots 150 therein. When the chains 156 engage the sprocket gears 158,however, they and the fingers 154 are elevated to the level of the runsI56b and the erect fingers move upwardly and enter the slots 150 behindthe product units 117 which are being delivered by the-continuouslymoving flights 142 of the crossover conveyor mechanism onto the slottedapron or extension I49. Consequently, as clearly indicted in FIGS. 14and 15, the elevated fingers 154 at this time will begin to push a pairof superposed product units 117 in unison toward the discharge end ofthe apparatus. The upper product unit 117' has been kept laterallysquared and aligned by the action of the blade 145-as the unit is pusheddiagonally through the crossover mechanism. When the two product units117 have been pushed by the fingers beyond the slotted extension 149,the units will move into stacked registering relation as shown at theleft-hand end of FIG. 15 and the fingers 154 still passing between thespaced bars 131 will deliver the stacked product units to thedischargeend of the apparatus for further handling as may be desired byother equipment.

While the plate 132 and extension 149 for clarity are shown adjustedupwardly to a level position in FIG. 15, it should be remembered thatthe crossover structure can be adjusted by turning the handle 140 sothat the extension 149 is very close to the tops of the lower productunits 1 l7 sliding over the bars 131. With proper adjustment, there isonly the thickness of the plate.132 between the upper and lower productunits when they clear the extension 149 and assume stacked relationship.Therefore any appreciable drop free fall of the tender product isavoided and the product units move continuously and gently into stackedrelationship with a sliding movement under influence of the fingers 154.

To assure final aligning and squaring of the stacked product units atthe discharge end of the apparatus, a longitudinal alignment plate isfixedly mounted at the inner side of the bed formed by the bars v131'.This alignment plate preferably extends under the extension 149 of plate132. Before two product units 117 are stacked on and under extension149, a strong jet of air from airjet nozzles 170 opposite the plate 169nudges the product units transversely against the alignment plate whichis at right angles to the row of fingers I54 pushing the product unitsatthis time. Preferably separate airjets act on the upper and lowerproduct units 117 of a given pair. This assures final squaring up andregistry of the product units even before they move into stackedrelation at the end of the extension 149. The airjet from the nozzles170 may be activated automatically by a valve 171, FIG. 15, having anactuator arm 172 engaged by an element 173 on each bar or flight 155 asthe lower run 1560 passes the valve. The opening of the valve 171intermittently sends compressed air through a pipe 174 to the airjetnozzles 170 for the stated purpose.

SUMMARY OF OPERATION The main .drive motor 76 and output gearingproduces operation of the infeed belts 35, rapid infeed rollers 68 and69, turnover mechanism, conveyor belts 127 and 128, crossover conveyorchains 143 and chains 156 and 160 of the pusher finger conveyor all inunison. These various components are locked together in their drives forproper-synchronism and timing.

With the above situation prevailing, the product units 117, such as rollclusters coming from a depanner, are allowed to accumulate at themarshaling station 29 having the infeed belts 35. Initially, the leadingproduct units or clusters are held up by the sponge rollers 68 and 69until both lanes are filled with product units at the marshalingstation. This is before the rapid infeed rollers 68 and 69 begin toturn. Subsequently, all leading product units in the two rows are heldup or restrained by the holddown grids 40 and 41.

It should be borne in mind that the product units enter the marshalingstation in the two rows either bottom side up or bottom side down inboth rows or either row. This is why the method and apparatus is madeflexible with respect to. the lateral positioning of the turnovermechanism over either product row or over both rows, in some instances,where plural inverting is required and is accomplished with side-by-sideidentical turnover mechanisms.

With the situation illustrated in the drawings where it is desired toinvert the product units in one row only, the operation continues in thefollowing manner. The holddown grids 40 and 41, when down, press theleading product units down against the rods 39 to restrain them whilethe slack belts 35 yield and simply slide beneath the product units.Photoelectric cells, not shown, may be utilized to detect the presenceof product units entering the rapid infeed rollers 68 and 69 and leavingthis area. Such detection means can be used -to control the operation ofthe holddown grids 40 and 41 thereby properly timing the release of theleading product units for entry into the rapid infeed rollers anddelivery into the turnover mechanism and onto the conveyor section 118for the row which is not utilizing a turnover mechanism. Numerousvariations in the control and timing means can be employed at this partof the apparatus and here the apparatus has a wide range of versatilityin its operation.

In any event, the holddown grids 40 and 41 elevate in proper sequence torelease a leading product unit from the marshaling station in each rowafter the rapid infeed rollers 68 and 69 have propelled a product unit117 into the passage 95 of the turnover mechanism. As shown by thespacing of the product units 117 at the left-hand portion of FIG. 1,there is a time delay interval in the operation of grids 40 and 41 toassure a proper lateral relationship of adjacent products units in thetwo rows following the inverting operation in the one row.

Following the inverting operation at the station 31 which has alreadybeen described in full detail, the product units in the two rows advanceon the belts 127 and 128 leading respectively to the slide bars 131 andto the slightly elevated crossover conveyor mechanism. The operation ofthese components has been described in detail and need not be repeated.Finally, as described, the companion product units emerge from theapparatus in accurately stacked relation for passage on to packagingequipment or the like.

In FIG. 18 of the drawings, there is shown somewhat diagrammatically amodification of the apparatus at the inlet side of the turnover station31. In this figure, rapid infeed rollers 68a and 69a are arrangedsomewhat closer to the turnover mechanism than in the first embodimentshown in FIG. 10. Additionally, the previously described guide rollermeans 38 between the rapid infeed rollers and the turnover mechanism hasbeen eliminated and also the guide roller means 37 is eliminated, FIG.10. In place of this arrangement, infeed conveyor belts 35a terminateahead of infeed rollers 68a and 69a and engage a guide roller 380 atapproximately the level of the roller 69a. Relatively small transferrollers 39a are disposed on opposite sides of infeed roller 69a, andassure a smooth transferring of the product units from the belts 35a tothe rapid infeed rollers and from these rollers into the chamber formedbetween the plates 94 of the turnover mechanism.

The advantage of the construction in FIG. 18 is that the belts 350 nolonger pass between the infeed rollers as depicted in FIG. 10 and thenecessity for forming the lower infeed roller in segments suchas shownat 74 in FIGS. 6 and 9 is eliminated, and the lower infeed roller, likethe upper one, may be formed in continuous sections. The construction isconsiderably simpler and more economical. The general mode of operationof the apparatus is not effected at all by this modification and,

a are identical with the first embodiment.

The methods and apparatus are characterized by simplicity, speed ofoperation, and reliability, without damage to the product. The apparatusis highly versatile, as explained. lts advantages should be readilyapparent to those skilled in the art.

it is to. be understood that the forms of the invention herewith shownand described are to be taken as a preferred example of the same, andthat various changes in the shape, size and arrangement of parts may berestored to, without departing from the spirit of the invention or scopeof the subjoined claims.

We claim:

l. A method of arranging product units comprising marshalling movingplural product units in two discrete rows, stopping movement of theleading product units in a transversely aligned condition, releasing andadvancing leading product units in the two rows and temporarilyrestraining the following unit in said rows, moving the product unit inone row diagonaly toward and over the companion moving product unit inthe other row while maintaining transverse alignment until the pair ofproduct units in the two rows are substantially in superposed relation,and then advancing the superposed and vertically separated pair ofproduct units in a manner to establish and maintain vertical alignmenttransversely of the direction of movement while retaining theirsuperposed and vertically separated relation and depositing the topproduct unit on the bottom product unit while maintaining said verticalalignment transversely of the direction of movement to produce atransversely aligned stack of product units.

2. A method of arranging product units as defined by claim 1, and theintermediate step of inverting each product unit in at least one rowfollowing the releasing of the product units from the marshaling zoneand prior to said diagonal movement.

3. A method of arranging product units as defined by claim 2, andwherein said inverting step comprises turning over each product unitwithout displacing it laterally from its primary path of movement.

4. A method of arranging product units as defined by claim 1, and theadditional step of engaging each stacked pair of product units altertheir movement into stacked relationship to assure their longitudinalalignment and registration in the stack.

S. A method of arranging product units as defined by claim 4, whereengagement to assure longitudinal alignment and registration comprisesdirecting a fluid jet toward one side of the stack while engaging theopposite side of the stack with an abutment member.

6. A method of arranging product units comprising advancing a spaced andtransversely aligned pair of product units in two discrete rows,directing the product unit of one row on a diagonal'path toward therelated unit of the other row while the unit of the other row continuesto be advanced and maintaining the squareness and transverse alignmentof the product unit on said diagonal path until said related productunits from the two rows become substantially superposed, and thenengaging the superposed pair of product units with a common movingelement to further advance the superposed and vertically separated pairof product units in a manner to establish and maintain verticalalignment transversely of the direction of movement while maintainingvertical separation of the product units and deposition the top productunit on the bottom product unit while maintaining said verticalalignment 'transverselyolthe direction of movement-to produce atransversely aligned stack of product units.

7. A method of arranging product units as defined by claim 6, andslidably supporting the product units moving on the diagonal path at anelevation slightly above the product units advancing in said other row,and said common moving element causing the product units sliding on theelevated d'ngonal path to move off of the support on which they aresliding and; to then become stacked with the underlying product units ofthe superposed pairs of units.

8. A method of arranging product units as defined by claim 2, andreleasing the leading product units in one row after the lapsing of apredetermined time delay interval following the release of correspondingproduct units in the other row.

9. A method of arranging product units as defined by claim 6, and theadditional step of inverting each product unit inat least one of saidrows during said advancing of the product units.

10. Apparatus for handling product units comprising power conveyor meansfor moving product units from a marshaling station in two discrete rows,21 diagonal crossover mechanism receiving the moving product units inone row and including means to convey the product units from said onerow on a diagonal path toward superposed relation with correspondingproduct units of the other row, said crossover mechanism furtherincluding means to support the product units moving on said diagonalpath at an elevation above the product units of said other row whilemaintaining transverse alignment of said corresponding product units,and an additional conveyor means common to the product units on saiddiagonal path and in said other row and engaging pairs of saidsuperposed product units in a manner to establish and maintain verticalalignment transversely of the direction of movement'while maintainingvertical separation of the product units, and advancing the superposedtransversely aligned pairs together until the upper unit of each pair isremoved from said supporting means and thereby rests upon the lowerproduct unit of the pair in stacked relation.

11. Apparatus for handling product units as defined by claim 10, whereinsaid means to support the product units moving on said diagonal pathcomprises a generally horizontal plate over which the product units aremoved by the conveyor means of the crossover mechanism, said platehaving a slotted terminal portion overlying the conveyor means for theproduct units in said other row, and said additional conveyor meansincluding spaced pusher elements which propel the product units of saidother row and rise through the slots of said terminal portion to alsoengage the product units deposited thereon in said superposed relationby the conveyor means of the crossover mechanism.

12. Apparatus for handling product units as defined by claim 11, andmeans to adjust the height of at least the end of the crossovermechanism carrying said slotted terminal portion.

13. Apparatus for handling product units as defined by claim 11, andwherein the conveyor means for'the product units in said other rowincludes a substantially level portion consisting of stationary parallelspaced bars having passages between them and through which passages saidpusher elements also rise to engage rearwardly of the product unitsthereon.

14. The apparatus of claim 10, and a turnover mechanism for productunits moving in one of said rows in advance of said crossover mechanism.

15. The apparatus of claim 14, and means supporting said turnovermechanism and operable to raise the mechanism to an inactive positionand also allowing the mechanism to be shifted laterally from onediscrete row to the other row for use in inverting the product units ofthe other row.

16. The apparatus of claim 14, wherein said turnover mechanism comprisesa relatively stationary support structure, a rotary assembly on saidsupport structure, means tonning a turnover compartment on the rotaryassembly adapted to receive individual product units from the conveyormeans while in a substantially level position, and intermittentlyoperable pusher device within said compartment forming an abutment toengage product units introduced into the compartment and later ejectingsuch product units from the compartment, and mechanism to rotate therotary assembly intermittently and move said pusher deviceintermittently from one end of said compartment to the opposite end andto maintain the pusher device stationary during the rotation of theassembly.

17. The apparatus of claim 16, wherein said turnover compartment isfonned by a pair of spaced parallel plates and the distance between theplates is sufficient to accommodate the thickness of one product unit.

18. The apparatus of claim 16, wherein said mechanism comprises at leastone drive chain for said rotary assembly and pusher device having aconnection with the pusher device and assembly and power means to movethe drive chain on a substantially D-shaped path, the straight side ofsaid path defining movement of the pusher device and the arcuate portionof the path defining rotary movement of said assembly.

19. The apparatus of claim 18, and wherein the rotary assembly comprisesat least one low-friction bearing having an outer race secured to saidsupport structure and a freely rotating inner race, said means formingthe turnover compartment secured to the inner race.

20; The apparatus of claim 19, and linear guide rod means for the pusherdevice secured to said inner race and turning therewith.

21. The apparatus of claim 13, and mechanism connected with said pusherelements and maintaining them upright at all times.

22. The apparatus of claim 21, wherein said mechanism comprises endlessdrive chains for said pusher elements, flights connected with said drivechains and carrying pusher elements in spaced apart rows and with theelements spaced laterally in each row, and an additional endless chainnear one of the drive chains and being offset longitudinally relativethereto and pusher element erecting links interconnecting saidadditional chain and said one chain at each flight.

23. The apparatus of claim 10, and wherein the conveyor means of thecrossover mechanism comprises spaced flights extending at right anglesto said discrete rows and diagonally of the path defined by thecrossover mechanism, alignment blades carried by said flights andextending forwardly thereof and substantially at right angles theretoand ooacting with the flights to maintain the squareness and lateralalignment of product units moving on said diagonal path, and endlesschain drive means for said flights.

24. The apparatus of claim 23, wherein the chain drive means for saidflights is a pair of endless chains adjacent the sidewalls of thediagonal crossover mechanism including upper runs spaced substantiallyabove the floor of the crossover mechanism and lower runs arranged closeto said floor, whereby said flights may push the product units over saidfloor slidably in one direction, and means for maintaining said flightserect as they travel with said chains.

25. The apparatus of claim 24, wherein the erecting means comprisesroller carriages on said flights engageable with the floor of thecrossover mechanism along said lower run, and an elevated carn track onone sidewall of the crossover mechanism engageable with said carriagesalong said upper runs.

26. The apparatus of claim 10, wherein said power conveyor meanscomprises a product infeed conveyor conveyor section includingrelatively slack infeed belts supporting the product units at saidmarshaling station, substantially rigid rods arranged slightly below thebelts and between the belts at the marshaling station, and verticallymovable product holddown grids above the belts at the marshaling stationoperable to press product units against the rods for restraining theunits while the slack belts slide beneath the product units.

27. The apparatus of claim 10, and power means connected with theholddown grids to raise and lower the same relative to said beltsindependently.

28. The apparatus of claim 27, wherein the power means to raise andlower the grids independently is a cylinder piston unit connected witheach grid near the forward end thereof.

29. The apparatus of claim 28, and means to bodily adjust the elevationof the cylinder piston units.

30. The apparatus of claim 26, and a pair of relatively large softcompressible product infeed rollers closely following said infeedconveyor section and holddown grids and adapted to receive between themleading product units released by the holddown grids and advance suchproduct units forwardly at increased speed toward further apparatuscomponents without damaging said product units.

31. The apparatus of claim 30, and a product unit turnover deviceclosely following the infeed rollers and having a shallow productcompartment to receive product units from the infeed rollers preparatoryto inverting such product units.

32. Apparatus for handling product units comprising a marshaling stationincluding product infeed conveyor sections and means to interrupt themovement of product units on the infeed conveyor sections so that asubstantial number of product units can accumulate at the marshalingstation in two discrete rows, a product-inverting mechanism for theproduct units in at least one row downstream form the marshalingstation, a product rapid infeed mechanism between the marshaling stationand said inverting mechanism to deliver individual product units in acontrolled and timed sequence from the marshaling station to theinverting mechanism, downstream product conveyor means for product unitsin the two rows following the inverting mechanism, a crossover conveyordownstream of said last-named conveyor means to carry product units inone row on a diagonal path toward and above corresponding product unitsof the second row, and an additional conveyor means common to theproduct units of the two rows near the discharge end of the crossoverconveyor engageable with product units from both rows arranged insuperposed pairs and delivering the same in stacked relationship to adischarge end of the apparatus.

33. The apparatus of claim 32, wherein the rapid infeed mechanismcomprises a pair of infeed rollers in substantially vertically spacedrelation, and transfer roller means on opposite sides of the infeedrollers and between such rollers and the infeed conveyor sections andinverting mechanism.

34. The apparatus of claim 33, and wherein the tops of said infeedconveyor sections, transfer roller means and the lowermost infeed rollerlie substantially in a common plane in advance of the product invertingmechanism.

35. A method of stacking one product unit upon another comprising:

moving the product unit in one row toward and over the product unit inthe other row while maintaining transverse alignment of the units,

advancing the resultant superposed and vertically separated productunits in a manner to establish and maintain vertical alignmenttransversely of the direction of movement while maintaining verticalseparation of the product units, and

depositing the top product unit on the bottom product unit whilemaintaining said vertical alignment transversely of the direction ofmovement to produce a transversely aligned stack of product units.

36. Apparatus for stacking one product unit upon another comprising:

means for moving the product unit in one row toward and over the productunit in the other row while maintaining transverse alignment of theunits,

means for advancing the resultant superposed and vertically separatedproduct units in a manner to establish and maintain vertical alignmenttransversely of the direction of movement while maintaining verticalseparation of the product units, and

means for depositing the top product unit on the bottom product unitwhile maintaining said vertical alignment transversely of the directionof movement to produce a transversely aligned stack of product units.

37. A method as defined in claim 34 including means for aligning thetransversely aligned stack longitudinally of the direction of movement.1

38. Apparatus as defined in claim 36 and including means for aligningthe transversely aligned stack longitudinally of the direction ofmovement.

1. A method of arranging product units comprising marshalling movingplural product units in two discrete rows, stopping movement of theleading product units in a transversely aligned condition, releasing andadvancing leading product units in the two rows and temporarilyrestraining the following units in said rows, moving the product unit inone row diagonally toward and over the companion moving product unit inthe other row while maintaining transverse alignment until the pair ofproduct units in the two rows are substantially in superposed rElation,and then advancing the superposed and vertically separated pair ofproduct units in a manner to establish and maintain vertical alignmenttransversely of the direction of movement while retaining theirsuperposed and vertically separated relation and depositing the topproduct unit on the bottom product unit while maintaining said verticalalignment transversely of the direction of movement to produce atransversely aligned stack of product units.
 2. A method of arrangingproduct units as defined by claim 1, and the intermediate step ofinverting each product unit in at least one row following the releasingof the product units from the marshaling zone and prior to said diagonalmovement.
 3. A method of arranging product units as defined by claim 2,and wherein said inverting step comprises turning over each product unitwithout displacing it laterally from its primary path of movement.
 4. Amethod of arranging product units as defined by claim 1, and theadditional step of engaging each stacked pair of product units aftertheir movement into stacked relationship to assure their longitudinalalignment and registration in the stack.
 5. A method of arrangingproduct units as defined by claim 4, where said engagement to assurelongitudinal alignment and registration comprises directing a fluid jettoward one side of the stack while engaging the opposite side of thestack with an abutment member.
 6. A method of arranging product unitscomprising advancing a spaced and transversely aligned pair of productunits in two discrete rows, directing the product unit of one row on adiagonal path toward the related unit of the other row while the unit ofthe other row continues to be advanced and maintaining the squarenessand transverse alignment of the product unit on said diagonal path untilsaid related product units from the two rows become substantiallysuperposed, and then engaging the superposed pair of product units witha common moving element to further advance the superposed and verticallyseparated pair of product units in a manner to establish and maintainvertical alignment transversely of the direction of movement whilemaintaining vertical separation of the product units and deposition thetop product unit on the bottom product unit while maintaining saidvertical alignment transversely of the direction of movement to producea transversely aligned stack of product units.
 7. A method of arrangingproduct units as defined by claim 6, and slidably supporting the productunits moving on the diagonal path at an elevation slightly above theproduct units advancing in said other row, and said common movingelement causing the product units sliding on the elevated diagonal pathto move off of the support on which they are sliding and to then becomestacked with the underlying product units of the superposed pairs ofunits.
 8. A method of arranging product units as defined by claim 2, andreleasing the leading product units in one row after the lapsing of apredetermined time delay interval following the release of correspondingproduct units in the other row.
 9. A method of arranging product unitsas defined by claim 6, and the additional step of inverting each productunit in at least one of said rows during said advancing of the productunits.
 10. Apparatus for handling product units comprising powerconveyor means for moving product units from a marshaling station in twodiscrete rows, a diagonal crossover mechanism receiving the movingproduct units in one row and including means to convey the product unitsfrom said one row on a diagonal path toward superposed relation withcorresponding product units of the other row, said crossover mechanismfurther including means to support the product units moving on saiddiagonal path at an elevation above the product units of said other rowwhile maintaining transverse alignment of said corresponding productunits, and an additional conveyor means common to the product units onsaid Diagonal path and in said other row and engaging pairs of saidsuperposed product units in a manner to establish and maintain verticalalignment transversely of the direction of movement while maintainingvertical separation of the product units, and advancing the superposedtransversely aligned pairs together until the upper unit of each pair isremoved from said supporting means and thereby rests upon the lowerproduct unit of the pair in stacked relation.
 11. Apparatus for handlingproduct units as defined by claim 10, wherein said means to support theproduct units moving on said diagonal path comprises a generallyhorizontal plate over which the product units are moved by the conveyormeans of the crossover mechanism, said plate having a slotted terminalportion overlying the conveyor means for the product units in said otherrow, and said additional conveyor means including spaced pusher elementswhich propel the product units of said other row and rise through theslots of said terminal portion to also engage the product unitsdeposited thereon in said superposed relation by the conveyor means ofthe crossover mechanism.
 12. Apparatus for handling product units asdefined by claim 11, and means to adjust the height of at least the endof the crossover mechanism carrying said slotted terminal portion. 13.Apparatus for handling product units as defined by claim 11, and whereinthe conveyor means for the product units in said other row includes asubstantially level portion consisting of stationary parallel spacedbars having passages between them and through which passages said pusherelements also rise to engage rearwardly of the product units thereon.14. The apparatus of claim 10, and a turnover mechanism for productunits moving in one of said rows in advance of said crossover mechanism.15. The apparatus of claim 14, and means supporting said turnovermechanism and operable to raise the mechanism to an inactive positionand also allowing the mechanism to be shifted laterally from onediscrete row to the other row for use in inverting the product units ofthe other row.
 16. The apparatus of claim 14, wherein said turnovermechanism comprises a relatively stationary support structure, a rotaryassembly on said support structure, means forming a turnover compartmenton the rotary assembly adapted to receive individual product units fromthe conveyor means while in a substantially level position, andintermittently operable pusher device within said compartment forming anabutment to engage product units introduced into the compartment andlater ejecting such product units from the compartment, and mechanism torotate the rotary assembly intermittently and move said pusher deviceintermittently from one end of said compartment to the opposite end andto maintain the pusher device stationary during the rotation of theassembly.
 17. The apparatus of claim 16, wherein said turnovercompartment is formed by a pair of spaced parallel plates and thedistance between the plates is sufficient to accommodate the thicknessof one product unit.
 18. The apparatus of claim 16, wherein saidmechanism comprises at least one drive chain for said rotary assemblyand pusher device having a connection with the pusher device andassembly and power means to move the drive chain on a substantiallyD-shaped path, the straight side of said path defining movement of thepusher device and the arcuate portion of the path defining rotarymovement of said assembly.
 19. The apparatus of claim 18, and whereinthe rotary assembly comprises at least one low-friction bearing havingan outer race secured to said support structure and a freely rotatinginner race, said means forming the turnover compartment secured to theinner race.
 20. The apparatus of claim 19, and linear guide rod meansfor the pusher device secured to said inner race and turning therewith.21. The apparatus of claim 13, and mechanism connected with said pusherelements and maintaining them Upright at all times.
 22. The apparatus ofclaim 21, wherein said mechanism comprises endless drive chains for saidpusher elements, flights connected with said drive chains and carryingpusher elements in spaced apart rows and with the elements spacedlaterally in each row, and an additional endless chain near one of thedrive chains and being offset longitudinally relative thereto and pusherelement erecting links interconnecting said additional chain and saidone chain at each flight.
 23. The apparatus of claim 10, and wherein theconveyor means of the crossover mechanism comprises spaced flightsextending at right angles to said discrete rows and diagonally of thepath defined by the crossover mechanism, alignment blades carried bysaid flights and extending forwardly thereof and substantially at rightangles thereto and coacting with the flights to maintain the squarenessand lateral alignment of product units moving on said diagonal path, andendless chain drive means for said flights.
 24. The apparatus of claim23, wherein the chain drive means for said flights is a pair of endlesschains adjacent the sidewalls of the diagonal crossover mechanismincluding upper runs spaced substantially above the floor of thecrossover mechanism and lower runs arranged close to said floor, wherebysaid flights may push the product units over said floor slidably in onedirection, and means for maintaining said flights erect as they travelwith said chains.
 25. The apparatus of claim 24, wherein the erectingmeans comprises roller carriages on said flights engageable with thefloor of the crossover mechanism along said lower run, and an elevatedcam track on one sidewall of the crossover mechanism engageable withsaid carriages along said upper runs.
 26. The apparatus of claim 10,wherein said power conveyor means comprises a product infeed conveyorconveyor section including relatively slack infeed belts supporting theproduct units at said marshaling station, substantially rigid rodsarranged slightly below the belts and between the belts at themarshaling station, and vertically movable product holddown grids abovethe belts at the marshaling station operable to press product unitsagainst the rods for restraining the units while the slack belts slidebeneath the product units.
 27. The apparatus of claim 10, and powermeans connected with the holddown grids to raise and lower the samerelative to said belts independently.
 28. The apparatus of claim 27,wherein the power means to raise and lower the grids independently is acylinder piston unit connected with each grid near the forward endthereof.
 29. The apparatus of claim 28, and means to bodily adjust theelevation of the cylinder piston units.
 30. The apparatus of claim 26,and a pair of relatively large soft compressible product infeed rollersclosely following said infeed conveyor section and holddown grids andadapted to receive between them leading product units released by theholddown grids and advance such product units forwardly at increasedspeed toward further apparatus components without damaging said productunits.
 31. The apparatus of claim 30, and a product unit turnover deviceclosely following the infeed rollers and having a shallow productcompartment to receive product units from the infeed rollers preparatoryto inverting such product units.
 32. Apparatus for handling productunits comprising a marshaling station including product infeed conveyorsections and means to interrupt the movement of product units on theinfeed conveyor sections so that a substantial number of product unitscan accumulate at the marshaling station in two discrete rows, aproduct-inverting mechanism for the product units in at least one rowdownstream form the marshaling station, a product rapid infeed mechanismbetween the marshaling station and said inverting mechanism to deliverindividual product units in a controlled and timed sequence from themarshaling station to the inverting mechanism, downstReam productconveyor means for product units in the two rows following the invertingmechanism, a crossover conveyor downstream of said last-named conveyormeans to carry product units in one row on a diagonal path toward andabove corresponding product units of the second row, and an additionalconveyor means common to the product units of the two rows near thedischarge end of the crossover conveyor engageable with product unitsfrom both rows arranged in superposed pairs and delivering the same instacked relationship to a discharge end of the apparatus.
 33. Theapparatus of claim 32, wherein the rapid infeed mechanism comprises apair of infeed rollers in substantially vertically spaced relation, andtransfer roller means on opposite sides of the infeed rollers andbetween such rollers and the infeed conveyor sections and invertingmechanism.
 34. The apparatus of claim 33, and wherein the tops of saidinfeed conveyor sections, transfer roller means and the lowermost infeedroller lie substantially in a common plane in advance of the productinverting mechanism.
 35. A method of stacking one product unit uponanother comprising: moving the product unit in one row toward and overthe product unit in the other row while maintaining transverse alignmentof the units, advancing the resultant superposed and verticallyseparated product units in a manner to establish and maintain verticalalignment transversely of the direction of movement while maintainingvertical separation of the product units, and depositing the top productunit on the bottom product unit while maintaining said verticalalignment transversely of the direction of movement to produce atransversely aligned stack of product units.
 36. Apparatus for stackingone product unit upon another comprising: means for moving the productunit in one row toward and over the product unit in the other row whilemaintaining transverse alignment of the units, means for advancing theresultant superposed and vertically separated product units in a mannerto establish and maintain vertical alignment transversely of thedirection of movement while maintaining vertical separation of theproduct units, and means for depositing the top product unit on thebottom product unit while maintaining said vertical alignmenttransversely of the direction of movement to produce a transverselyaligned stack of product units.
 37. A method as defined in claim 34including means for aligning the transversely aligned stacklongitudinally of the direction of movement.
 38. Apparatus as defined inclaim 36 and including means for aligning the transversely aligned stacklongitudinally of the direction of movement.